Water softener for a 4 bedroom house with 2 people
Currently we have 2 people in the house (4 bedroom, 2 baths) with the possibility of more later (kids or housemate). Our water hardness is 18 gpg with a max of 23 according to our water quality report. Iron is negligible. I measured 5 GPM at the bathtub. Neighbors have water softeners but all seem to be undersized.
I'm planning on purchasing a Fleck (with basket, gravel, and bypass) from Ohio Pure Water. From what I read, a 2.5 cu resin tank would be good for 4 people but oversized for 2. Would a twin tank system be better? I'm not too sure on how size for 2 tanks. Do I aim for a 7 day regen 2 people and 3 days at 4 or 14d at 2 and 7d at 4? I want long term efficiency and I'm not concerned about upfront costs.